Process and device for producing corrugated board

ABSTRACT

In a process for manufacturing corrugated cardboard, corrugated cardboard is produced by gluing several individual webs (10, 11, 31) to each other by their mutually opposite surfaces. Several individual webs (10, 11, 31) are conveyed to an assembly point (A) and then moved over a heating device (38). The distance between the glue application points (B, C) and the assembly point (A) of the individual webs (10, 11) varies according to the speed of the webs.

BACKGROUND OF THE INVENTION

The invention relates to a process for producing corrugated board, aswell as a device for carrying out this process.

It is known to produce corrugated board by bringing together a number ofconstituent webs together and gluing them to one another. For example,with a double-double corrugated board, three constituent webs, namelytwo constituent webs of unilateral corrugated board and one smooth coverweb are brought together. It is known to supply these constituent websto a single junction point at which a heating device possibly adjoins aconveyor belt. In this known manufacturing process, it isdisadvantageous that the spacings between the adhesive applicationpoints for the constituent webs and the junction point for theconstituent webs are unnecessarily great. The required heat entry intothe constituent webs and the residual heat in the region of the junctionpoint of the constituent webs is usually insufficient. Furthermore, theadhesive mechanisms and thus the adhesive application point are disposedspaced apart from the junction point of the constituent webs,independently of the web speed. With increased web speed, there is thusthe danger that the moisture removal from the adhesive application isinsufficient before the constituent webs reach the junction point. Afavorable gluing together of the constituent webs then requires anunnecessarily long heating device via which the glued-togetherconstituent webs must be guided. At a lower web speed, too much moistureis removed from the adhesive. The adhesion is inadequate.

SUMMARY OF THE INVENTION

The object of the invention is to establish a process and a device whichmake it possible to assure the optimal moisture removal from theconstituent webs even at different web speeds and to assure the shortestpossible spacing between the preheating device and the adhesiveapplication point as well as between the adhesive application point andthe junction point of the constituent webs. Furthermore, the deviceshould have a compact design.

The invention attains the object of assuring the optimal moistureremoval of the adhesive application even with changeable web speed byvirtue of the fact that the spacing between the adhesive applicationpoint and the junction point is changed as a function of the web speed.

This achieves the advantage that for the optimal moisture removal, thespacing between the preheating device and the adhesive application pointof the constituent web and the junction point of the constituent web canbe selected to be as short as necessary, depending on the web speed. Theheating device that adjoins the junction point of the constituent webscan then be kept as short as possible.

According to one embodiment of the invention, a number of constituentwebs are conveyed to a single junction point. This produces a compactdesign of the device.

According to another embodiment of the invention, the adhesivemechanisms for the constituent webs are disposed one above the other. Itis furthermore possible to more simply embody the movement or positionchanging of the adhesive mechanisms and therefore of the adhesiveapplication point in relation to the junction point of the constituentwebs. In order to achieve the most compact design possible and to thusachieve optimal spacings, a corresponding structure of the adhesivemechanisms is required.

In order to improve the heat entry into the constituent web or into theboard web to be glued, the constituent webs are heated from both oftheir outer sides before and/or after the adhesive application.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be explained in detail below in conjunction with theaccompanying drawing showing a side view schematic representation of thedevice for manufacturing a corrugated board web out of a number ofconstituent webs.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The device 1 provides adhesive mechanisms 2, 3, preferably disposed oneabove the other. The adhesive mechanisms 2, 3 have a design that is notexplained in detail. They have adhesive transfer rolls 4, 5 that aredriven in the indicated arrow direction. These cooperate with meteringrolls 6, 7. The metered adhesive application is taken by the adhesivetransfer rolls 4, 5 and conveyed to the constituent webs 10, 11. Theadhesive supply is carried out via stationary tubes 8, 9 that are filledwith adhesive. Excess adhesive is wiped away from the metering rolls 6,7 via blades 42, 43 and supplied to a pump via catch channels 45, 46.The adhesive can emerge via openings 39, 40 in the tubes 8, 9 into thenip regions 41, 41'. It can first contact the adhesive transfer rolls 4,5 and is metered by the metering rolls 6, 7. The constituent webs 10, 11are unilateral corrugated board webs. They are comprised of a cover weband a corrugated web. The constituent webs 10, 11 rest with theircorrugated webs against the adhesive transfer rolls 4, 5 and are presseduniformly via compression elements 47, 48. By means of this, theadhesive is transferred from the adhesive transfer rolls 4, 5 onto theapexes of the corrugated webs.

The constituent webs 10, 11, which are arriving in the indicated arrowdirections are guided via preheating devices 15, 16. These can, forexample, be curved segments that are heated. They heat the cover webs ofthe constituent webs 10, 11. In addition, a heating-device 20, 21 can beprovided that heats the other, external side of the constituent web 10,11, i.e. the corrugated web. For example, a steam chamber can be usedfor this purpose.

The constituent web 10 is then supplied to the adhesive transfer roll 4via a deflecting roll 22, which is disposed so that adhesive beingsprayed from the constituent web 10 and from the adhesive transfer roll4 can be captured by the catch channel 45. In the lower adhesivemechanism 3, the sprayed adhesive is captured by a water-cooled adhesiveskirt 50 and supplied to the catch channel 46. Then, the constituent web11 reaches the stationary junction point A for the constituent webs 10,11, which is constituted by the roll pair 24. The rolls 22, 23, and 25can be heated.

The constituent web 11 is likewise supplied via the preheating device16, which has a heating device 21, e.g. in the form of a steam pressurechamber, and via a deflection roll 30 to the adhesive transfer roll 5 inthe indicated arrow direction. After adhesive application, it arrives atthe junction point A of the roll pair 24. The roll 30 can also beheated.

The adhesive mechanism 3 is embodied in approximately the same way asthe adhesive mechanism 2 and is not described further.

In the constituent web 11, the corrugated web is likewise orientedtoward the adhesive transfer roll 5.

Another constituent web 31, e.g. a smooth cover web, is supplied via adeflection roll 32 in the indicated arrow direction via a heating device33, which can be comprised, for example, of parallel heating platesdisposed one above the other. A deflection roll 34 is provided on oneend of the heating device 33. In this manner, the heating device 33carries out a two-sided heating of the cover web which constitutes theconstituent web 31.

The constituent web 31 travels from the heating device 33 to the bottomdeflection roll 25 of the roll pair 24, partially winds around this rolland as a bottom constituent web, constitutes the cover web for theunilateral corrugated board web disposed above it, above which in turn,the other unilateral corrugated board web is disposed, whose corrugatedweb is associated with the cover web disposed beneath it.

In a conventional manner, the deflection roll 23 can guide a conveyorbelt 35, which extends above the heating device 38 for the constituentwebs to be glued.

The adhesive mechanisms 2, 3 as well as the heating devices 15, 16, 20,21, and the deflection rolls 22, 30 are fastened to lateral plates 35.

These can be moved in an adjustable manner via rollers 36 on tracks 37.

Preferably the adhesive transfer rolls 4, 5 are disposed with theircentral axes in a vertical plane. When the rolling rack plates 35 aremoved, the spacings of the adhesive transfer points B, C in relation tothe junction point A of the constituent webs 10, 11 are changed. Thischange can be produced by means of corresponding movement as a functionof web speed. The movement can be selected manually, but can also occurautomatically as a function of web speed.

What is claimed is:
 1. A process for producing corrugated board,comprising the steps of:a) preheating a surface of each of a pluralityof webs using a preheating device for each of said webs; b) applying anadhesive coating to a surface of each of the plurality of webs at anadhesive application point using an adhesive application device for eachof said webs downstream from the preheating device; c) adhering togetherfacing surfaces of said webs at a junction point at a distance from eachadhesive application point to produce a corrugated board, at least oneof said facing surfaces having an adhesive coating thereon; d) heatingthe corrugated board; e) determining speed of travel of the webs; and f)moving the preheating devices and corresponding adhesive applicationdevices so as to adjust the distance between the adhesive applicationdevices and the junction point on the basis of the speed of travel ofthe webs.
 2. The process according to claim 1, wherein the adhesiveapplication devices are arranged one above another.
 3. The processaccording to claim 2, wherein the distance between the adhesiveapplication devices and the junction point is adjusted longitudinally.4. The process according to claim 1, wherein the webs are heated on bothsurfaces before the adhesive application.
 5. A device for producingcorrugated board by adhering together a plurality of webs, comprising:a)a plurality of adhesive coating devices for coating a face of aplurality of webs; b) a plurality of web preheating devices, eacharranged upstream of one of said adhesive coating devices; c) means foradhering together a plurality of webs having a face coated with adhesiveat a junction point which is spaced from the adhesive coating devices bya distance, to form corrugated board; d) a heating device arrangeddownstream of the junction point, for heating the corrugated board; e)means for moving the web preheating devices and corresponding adhesiveapplication devices as a unit to thereby adjust the distance dependingon the speed of travel of the web.
 6. The device according to claim 5,wherein the plurality of adhesive coating devices is arranged one on topof another.
 7. The device according to claim 5, wherein the preheatingdevices heat opposite faces of each web.
 8. The device according toclaim 5, wherein preheating devices and a corresponding adhesive coatingdevices are mounted on a single plate.